Adjustable stop

ABSTRACT

This patent discloses an attachment for an automatic lathe having a turret for mounting a series of tools which are operated in sequence automatically to produce a finished machined workpiece, in particular an attachment for a turret slide head having a tool mount which moves axially towards the chuck, and which at the forward end of its stroke, may be displaced laterally from its &#39;&#39;&#39;&#39;home&#39;&#39;&#39;&#39; position by a pusher mounted on a cross slide of the lathe. At the completion of the pusher stroke, the pusher retracts and the slide head is automatically returned to its &#39;&#39;&#39;&#39;home&#39;&#39;&#39;&#39; position, and it may be retracted axially of the chuck. In the illustrated slide head, a delay device retards the return of the head to its &#39;&#39;&#39;&#39;home&#39;&#39;&#39;&#39; position. This patent discloses a stop which permits automatic adjustment of the &#39;&#39;&#39;&#39;home&#39;&#39;&#39;&#39; position of the slide head to different settings in successive operations.

O United States Patent 1 1 3,581,610

[72] Invent rs John E. Burke 3,190,157 6/1965 Ciccarelli 82/5 Broomall; 3,363,491 1/1968 George 82/5 Edward J. Kaiser, Philadelphia, Pa.;

5:231? es'zxzzczkztfssoi' [21] Appl. No. 827,763 y [22] Filed May 26,1969 [45] F June 1971 ABSTRACT: This patent discloses an attachment for an auto- [73] Assignec J. Lonergan Company matic lathe having a turret for mounting a series of tools which Philadelphia, Pa. are operated in sequence automatically to produce a finished machined workpiece, in particular an attachment for a turret slide head having a tool mount which moves axially towards [54] the chuck, and which at the forward end of its stroke, may be g g displaced laterally from its home" position by a pusher U.S-

.L mounted on a cross lide of the lathe At the completion of he [51 Int. Cl B23b 5/46 pusher stroke, the pusher retracts and the slide head is auto- Of Search .1 maticany returned to home" position and may be retracted axially of the chuck. 1n the illustrated slide head, a [56] References C'ted delay device retards the return of the head to its home" posi- UNITED STATES PATENTS tion. This patent discloses a stop which permits automatic ad- 2,903,933 9/1959 Mackenzie 82/5 justment of the home" position of the slide head to different 3,121 ,357 2/1964 Skoglund et a1. 82/5 settings in successive operations.

PATENTED JUN H97! 3581.610

sum 1 or 4 INVENTORSZ JOHN E. BURKE EDWARD J. KAISER CHARLES .1- MYERS WWW/yaw AT'TYS,

PATENTED JUN 1191:

SHEET 2 OF 4 I if E INVENTORSZ JOHN E. BURKE EDWARD J. KAISER BY CHARLES J. MYERS ATTYS.

ADJUSTABLE STOP The present invention relates to automatic turret lathes, and has particularapplication to an automatic cyclic adjusting mechanism for a turret slide head having a tool mount which is displaceable laterally at the forward end of its stroke and automatically returns to its home" position.

Automatic turret lathes are used for performing automatically a series of sequential machining operations on workpieces, usually under the control of preset programming mechanism. Frequently, a thread'cutting operation is included in the sequence of operations which must be performed. The standard procedure for perfon'ning thread-cutting operations involves the use of thread-cutting attachments which form a screw thread in a single pass by dies and chasers which form the threads during a single pass of the turret which is timed in relation to the rotation of the chuck.

While effective to perform the desired machining operation, the use of dies and chasers is not entirely satisfactory in ships where there is a wide variety ofjobs to be performed. The dies may be used for only a limited range of diameters for the workpiece to be threaded, and the chasers must be selected for the particular thread form. Thus when a variety of thread forms are normally machined on workpieces of various diameters, the shop must maintain a large inventory of dies and chasers in order to perform all of the various thread-cutting operations which may be specified. If the particular die and chaser is not in stock, a considerable delay is normally experienced in obtaining the necessary tools from the supplier.

Threads may also be cut by using a conventional cutting tool'whieh is traversed along the work in timed relation to the rotation of the chuck, but to obtain a proper finish, it is neces sary to perform the thread-cutting operation in several passes, adjusting the depth of cut between successive passes. Such adjustments are not readily programmed for automatic operation and accordingly the formation of threads in this manner requires constant attendance of the machine operator with the attendant likelihood of introducing human error into the machine operations.

With the foregoing in mind, the present invention provides a novel adjusting mechanism for automatic turret lathes which provides adjustment of the depth of cut cyclically to afford programming of the automatic lathe to provide cuts of increasing depth on sequential passes of a cutting tool.

More particularly, the present invention provides an improved mechanism for a turret head slide assembly having a laterally displaceable slide head which adjusts the home" position of the slide head automatically.

In the preferred embodiment of the invention, the adjustable stop mechanism overrides the conventional fixed stop which determines the home position to which the slide head is returned after lateral displacement, the adjustable stop mechanism comprising a member having a series of abutments which are individually adjustable and are indexed automatically in sequence into registry with a stop element with each transverse displacement of the slide block.

All of the objects of the invention are more fully set forth hereinafter with reference to the accompanying drawings wherein:

FIG. 1 is a fragmentary view of an automatic turret lathe in end elevation as seen from the right'hand end;

FIG. 2 is a fragmentary view of the lathe in rear elevation, as seen from the line 22 of FIG. 1;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. I and showing in broken lines the sequence of position of the tool mount;

FIG. 4 is an enlarged fragmentary right-hand end elevation of the turret slide head embodying the present invention in its laterally displaced position, with portions broken away to more clearly illustrate the construction and arrangement of the parts;

FIG. 5 is an enlarged sectional view taken on the line 5-5 of FIG. 4;

FIG. 6 is a fragmentary view in end elevation similar to FIG. ll showing an alternate form of adjusting mechanisms;

FIG. 7 is a sectional view taken on line 77 of FIG. 6 illustrating in broken lines the positions of the indexing mechanism during transverse displacement of the slide block;

FIG. 8 is an enlarged sectional view taken on the line 8-8 of FIG. 6;

FIG. 9 is an inverted sectional view taken on the line 9-9 of FIG. 8;

FIG. I0 is a perspective view of the cam element as shown in broken lines in FIG. 8.

Referring now to the drawing, FIGS. I to 3 illustrate a lathe having a rotating chuck 22 at its left-hand end and a turret 23 at the other end which may be displaced axially of the chuck to perform machine operations on the exposed end of the workpiece 24 mounted in the chuck. In the present instance, a slide head assembly 25 is mounted in operative position on the turret which includes a slide block 33 fixedly mounted on the turret and a slide head 34 mounted for lateral displacement on the slide block. The turret is displaceable axially of the chuck by conventional drive means 26 which is operated in timed relation to the rotation of the chuck so as to advance and retract the machine tool 35, mounted in one of the toolmounting bores 36 of the slide head, toward and away from the work 24 mounted in the chuck for rotation on its axis. Front and rear cross slides37 are positioned on the lathe to register with the slide block when it is in its advanced limit position, and in the present instance a pusher 38 is mounted on the rear cross slide to engage the slide head 34 for displacing the same laterally on the slide block 33.

The slide head 34 is biased by spring means 39 toward a normal home" position so that the pusher 38 operates to displace the slide head against the bias of is associated spring means 39. Upon retraction of the pusher, the spring means returns the slide head to its home position. In the present instance, the slide head assembly includes a delay device 41 which retards the return movement of the slide head. The illustrated delay device comprises a hydraulic cylinder and piston assembly of conventional construction having valve means permitting free lateral displacement of the slide head from its home" position to its laterally offset position, but delaying return of the slide head to its home" position. In the present instance, with reference to FIG. 3, the tool 35 may perform its cutting operation while the slide head is in its home" position as the turret advances toward the chuck. At the forward limit of the pass of the turret 23, the tool 35 is in the position shown at 35' and the pusher 38 is then actuated to displace the slide head 34 laterally from its home position to thereby cause the tool to disengage the work 24 as shown at 35", and after retraction of the pusher, the turret may be retracted as the slide head returns slowly toward its home position under the control of the delay device 41, the tool therefore passing out of registry with the work prior to its return to the home position.

In accordance with the invention, means is provided to effect automatic adjustment of the home position when the slide head is displaced, so that the spring bias 39 returns the slide head 34 to an adjusted home position. Preferably the adjusted home" position will provide a slightly deeper cut than the previous home position so that the turret may be actuated again to provide a second and deeper cut. In the illustrated embodiment, the adjusting mechanism has a capability for providing six different *home" positions to which the slide head 34 is returned in sequence, and is designed to afford cyclic repetition of this sequence. Thus the machine may be set to provide six cuts of increasing depth by the tool 35 mounted in the slide head 34 in the operative station of the turret to complete a finished machine operation, for example thread formation, before the turret of the lathe is indexed to perform the next machining operation. In the present instance, the adjusting mechanism of the present invention overrides the conventional adjustment which determines the normal home position of the slide head on the slide block.

Referring now to the drawing, the illustrated adjusting mechanism is mounted on the trailing right-hand face of the slide head assembly and it comprises an adjusting bar and stop assembly 51 mounted on the slide block 33 and an adjustable abutment assembly 52 mounted on the slide head 34. The adjusting bar and stop assembly 51 includes an elongated adjusting bar 53 extending transversely, parallel to the path of displacement of the slide head 34. The bar 53 is mounted in spaced relation to the slide block 33, but a forward support arm 54 and a rear support arm 55, for adjustment longitudinally thereof by slotted connections indicated at 56 and 57 respectively. The rear support arm includes a depending stop foot 58 as shown in FIGSv I, 2 and 4. Intermediate the support arms 54 and 55, a cam element 61 (FIGS. 1, 3 and is mounted to depend below the bar 53. The cam element is mounted for longitudinal adjustment by clamping plates 62 and 63 which are interconnected through slots 59 and 60 in the bar 53. The cam 61 is pivotally adjustable on the clamp 62 by means of an adjustment indicated at 64 (FIG. I).

The assembly 52 is mounted to cooperate with the stop foot 58 and the cam element 61 of the assembly 51. To this end, the assembly 52 comprises a support bracket 68 mounted in spaced relation to the slide head 34 by a spacer block 69 and an extension arm 72. The bracket 68 is provided with a pair of front and rear bearing blocks 73 and 74 respectively which mount an indexing shaft 75 having a central pinwheel 76 (FIG. 4) which serves as an indexing ratchet. At the rear end of the indexing shaft 75, a rotary adjusting head 77 is mounted. The adjusting head 77 has an adjusting abutment stud 78 mounted therein at each of six equally spaced stations therearound. In the present instance, as shown in FIG. 2, the stations are positioned respectively at 2 oclock, 4 o'clock, 6 o'clock, 8 0- clock, oclock, and 12 oclock. The stud 78 at the 12 oclock station is in registry with the stop foot 58 so that when the support bracket 68 is carried rearwardly by the retraction of the slide head 34 under the bias of its spring means 39, the stud 78 engages the foot 58 to determine the home" position of the slide head. Thus, by varying the projection of the abutment studs 78 from the head 77, various the foot 58 to determine the home" positions may be provided as the different studs are indexed to the 12 oclock position. If it is desired to adjust the extension of all of the studs 78 simultaneously, an adjusting mechanism 79 is provided at the forward end of the shaft 75.

In order to index the shaft 75 to position the studs 78 suecessively in the 12 oclock station, an indexing pawl 82 is provided to cooperate with the pinwheel 76 for actuation by the cam 61 during displacement of the slide head 34. As shown in FIG. 5, the indexing pawl 82 is mounted on an indexing piston 83 within a cylinder 84 carried by the bracket 68 in registry with the pinwheel 76. The piston 83 is biased upwardly in the cylinder 84 by a spring 85 having a seat which is adjustable by a set screw 86 projecting through the bottom of the cylinder 84. At the top, the piston 83 mounts a follower wheel 88 in the plane of the cam 61 so that when the slide head 34 is displaced forwardly by the pusher 38, the cam 61 engages the follower wheel 88, pressing the piston 83 downwardly against the bias of the spring 85. During the downward travel of the piston 83, the indexing pawl 82 is pivoted counterclockwise against the bias of a spring 89 so as to clear the pins of the pinwheel 76. The cam 61 is adjusted on the bar 53 so that at the forward limit of the displacement of the slide head, the pawl 82 is displaced beyond the next pin on the pinwheel 76, engaging under the pin by the action of the spring 89. Thus when the slide head 34 is returned rearwardly and the wheel 88 disengages the cam 61, the spring 85 displaces the pawl 82 upwardly effecting rotation of the pinwheel 76, thereby indexing the shaft 75 to position the next abutment stud 78 at the 12 o'- clock station in registry with the stop foot 58. Thus the pinwheel 76 serves as a ratchet cooperable with the pawl 82 to effect angular indexing of the adjusting head 77. A leaf spring device 87 cooperates with the wheel 76 to serve as detent means for limiting the movement of the wheel and insuring re gistry of the abutment studs 78 in their respective stations.

It is noted that the pinwheel 76 has its pin positioned angularly thereabout corresponding to the angular position of the studs 78 in the adjusting head 77, in the present instance at 60 increments. It is apparent that more or less adjustments may be provided by increasing or decreasing the number of studs positioned around the adjusting head 77 and correspondingly increasing or decreasing the pins in the pinwheel 76. The selection of six stations around the adjusting head 77 not only provides a compact arrangement, but also provides a degree of flexibility in the operation of this device. By the use of six stations, the depth of cut may be adjusted in cycles of six increments. On the other hand, where six incremental adjustments are not required in each cycle, the adjusting head may provide 2 cycles of three incremental adjustments or 3 cycles of two incremental adjustments, as will be apparent to a skilled programmer.

In the alternate form of adjusting mechanism shown in FIGS. 6 through 10, the adjusting mechanism includes parts and elements which are identical to the mechanism illustrated in FIGS. 1 through 5. Such parts have been identified with identical reference numerals, and the description thereof will not be repeated here, the alteration residing in the indexing mechanism which operates to displace the indexing piston 83 and indexing pawl 82 to effect the incremental rotation of the shaft through the pinwheel 76. To this end, the piston 83 in this embodiment of the invention includes a follower element 188 having an angular surface 189 (see FIG. 6) facing forwardly ofthe lathe. The follower element 188 cooperates with a cam element 161 pivotally mounted on a carriage 162, as indicated at 163. The carriage 162 is slidable on the adjusting bar 53 by means of an elongated slide 153 which is guided for longitudinal displacement on the bar 53 by side plates 154 and 155 having a through bolt I56 slidably engaged in the slot 60 of the bar 53. Forward (leftward in FIGS. 6 and 7) sliding movement of the bar 153 is limited by an adjustable stop element 164 at the forward end of the bar 53 and a spring member 165 is (see FIG. 7) provided to bias the slide 153 forwardly against the stop 164.

In the operation of the device, as the slide head 34 is displaced to the left as shown in FIGS. 6 and 7, by the pusher 38, the follower 188 rides under the cam 16] and is depressed to displace the pawl 82 under the pin of the wheel 76 in preparation for indexing the shaft 75. In this embodiment of the invention, the follower 188 is free to pass beyond the cam 161 so that after passage beyond cam 161, the spring 85 (FIG. 5) is free to displace the piston 83 upwardly and effect indexing of the shaft 75. In this embodiment of the invention, as distinct from the embodiment of FIG. I through 5, the indexing therefore occurs at the forward limit position of the slide head 34 instead of during the rearward return stroke of the head.

To effect the downward displacement of the follower 188, the cam I61 (see FIG. 10) has an angular rear surface 191 which cooperates with the angular surface 189 to effect downward displacement of the piston 83. The forward edge of the cam 161 is provided with a beveled surface 192, which, after passage of the follower 188 beyond the cam 161 operates to effect outward pivotal movement of the cam 161 as indicated in broken lines in FIG. 8 to permit return passage of the follower 188 without being depressed.

In order to provide greater flexibility in the adjustment of the strokes, multiplier means is provided to displace the carriage 162 rearwardly concurrent with the forward displacement of the slide head 34 to insure passage of the follower 188 beyond the cam element 161. To this end, the slide element 153 projects rearwardly (rightwardly in FIGS. 6 and 7) beyond the rear edge of the fixed slide block 33, the terminal end 193 having a receptacle 194 for receiving a head 195 of an operator lever 196 which is pivoted to the slide block 33 by means of a pivotal mounting element 197 having an upstanding pivotal axis at 198. At the other side of the pivotal axis 198, the lever 196 has an adjustable extension 199 which is designed to be displaced by a pusher I38 mounted on the cross slide for movement with the pusher 38 described above.

Thus the slide 153 serves to multiply the relative displacement of the cam 161 and the follower 188. By adjusting the extension 199, and correspondingly adjusting the pusher 138, the displacement of the slide 153 may be regulated. For example, if it is desired to reduce the displacement of the slide head 34, the pusher 38 may be adjusted to accomplish this, but it is necessary to further increase the sliding movement of the carriage 162 to insure that the cam 161 is displaced sufficiently to pass beyond the follower 188 during its limited forward displacement with the slide head 34.

The arrangement herein provides for adjustment of the home position of the slide head during the period when the slide head is displaced laterally from its home" position. While the invention has been described in connection with a slide head assembly having a delayed return, and particularly in connection with the cutting of threads, it is apparent that the attachment may be applied to a slide head attachment which omits the delay mechanism.

While a particular embodiment of the invention has been herein illustrated and described, the invention is not limited to such disclosure but changes and modifications may be made therein and thereto, as will be apparent to those who are skilled in this field.

We claim:

1. In a lathe having a slide block member, a tool-carrying slide head member mounted on said slide block member for displacement toward and away from a home" position in which the tool engages the work, means to bias said slide head toward its home position, a pusher mounted for lateral displacement against said slide head to displace said slide head away from its home" position and the tool out of engagement with the work, an adjustable stop for determining said home position comprising an adjusting head mounted for indexing movement on one of said slide members, a series of abutment elements carried by said head, operable to be indexed in sequence into an operative station upon indexing movement of said adjusting head, said abutment elements being of different projection, indexing means for said head operable upon successive lateraldisplacements of said slide head member on said slide block member to index said head to carry said series of abutment elements successively into said operative station, and a stop foot on the other of said slide members in registry with said operative station to abut against the operative abutment element and thereby determine a different home position of said slide head for each of said abutment elements, and thus the degree of engagement of the tool with the work; the improvement wherein said indexing means comprises a ratchet member on said adjusting head, a pawl to drive said ratchet member, a cam follower on said pawl, cam means carried by the other of said slide members to displace said follower and thereby to drive said ratchet member upon each said displacement of said slide head member, means mounting said cam means on said other slide member for displacement, and an operator to effect displacement of said cam means oppositely to said follower to thereby multiply the relative displacement of said cam follower and said cam means.

2. A lathe according to claim 1 wherein said adjusting head is mounted for rotary indexing movement about an axis, and

said abutment elements are mounted in equal circumferentially-spaced relation about said axis so that continued indexing of said adjusting head effects cyclic repetition of said successive indexing of said series of abutment elements into said operative station.

3. A lathe according to claim 2 wherein said ratchet member comprises a wheel mounted in driving relation to and coaxial with said adjusting head.

4. A lathe according to claim 1 wherein said relative displacement causes said follower to pass beyond said cam means to complete the indexing operation of said indexing means during displacement of said slide head in one direction, and means to avoid displacement of said cam follower by said cam means upon displacement of said slide head in the other direction.

5. A lathe according to claim 1 including first adjusting means for adjusting the projection of each abutment element individually relative to said adjusting head, and second adjusting means for adjusting said adjusting head to control the projection of the series of abutment means in unison.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,581,610 Dated June 1, 1971 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 18, change "ships" to --shops--.

Column 3, lines 37 and 38; delete "the foot 58 to determine the" Signed and sealed this 19th day of October 1971 (SEAL) Attast:

EDWARD M.FLETCHER,JR. ROBERT GOT'I'SCHALK Attesting Officer Acting Commissioner of Patents FORM po'mso USCOMM-DC scans-pas U S. GOVER-MENT PHINYNG OFFICE I959 U-366'33l 

1. In a lathe having a slide block member, a tool-carrying slide head member mounted on said slide block member for displacement toward and away from a ''''home'''' position in which the tool engages the work, means to bias said slide head toward its ''''home'''' position, a pusher mounted for lateral displacement against said slide head to displace said slide head away from its ''''home'''' position and the tool out of engagement with the work, an adjustable stop for determining said ''''home'''' position comprising an adjusting head mounted for indexing movement on one of said slide members, a series of abutment elements carried by said head, operable to be indexed in sequence into an operative station upon indexing movement of said adjusting head, said abutment elements being of different projection, indexing means for said head operable upon successive lateral displacements of said slide head member on said slide block member to index said head to carry said series of abutment elements successively into said operative station, and a stop foot on the other of said slide members in registry with said operative station to abut against the operative abutment element and thereby determine a different ''''home'''' position of said slide head for each of said abutment elements, and thus the degree of engagement of the tool with the work; the improvement wherein said indexing means comprises a ratchet member on said adjusting head, a pawl to drive said ratchet member, a cam follower on said pawl, cam means carried by the other of said slide members to displace said follower and thereby to drive said ratchet member upon each said displacement of said slide head member, means mounting said cam means on said other slide member for displacement, and an operator to effect displacement of said cam means oppositely to said follower to thereby multiply the relative displacement of said cam follower and said cam means.
 2. A lathe according to claim 1 wherein said adjusting head is mounted for rotary indexing movement about an axis, and said abutment elements are mounted in equal circumferentially-spaced relation about said axis so that continued indexing of said adjusting head effects cyclic repetition of said successive indexing of said series of abutment elements into said operative station.
 3. A lathe according to claim 2 wherein said ratchet member comprises a wheel mounted in driving relation to and coaxial with said adjusting head.
 4. A lathe according to claim 1 wherein said relative displacement causes said follower to pass beyond said cam means to complete the indexing operation of said indexing means during displacement of said slide head in one direction, and means to avoid displacement of said cam follower by said cam means upon displacement of said slide head in the other direction.
 5. A lathe according to claim 1 including first adjusting means for adjusting the projection of each abutment element individually relative to said adjusting head, and second adjusting means for adjusting said adjusting head to control the projection of the series of abutment means in unison. 